<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<h3><span id="counter">5</span>秒以后自动跳转到百度</h3>
		<script>
			var span = document.getElementById('counter');
			var num = 5;
			setTimeout(function() {
				num -= 1;
				if (num > 0) {
					span.textContent = num;
					setTimeout(arguments.callee, 1000);
				} else {
					location.href = 'http://www.baidu.com';
				}
			}, 1000);
		</script>
	</body>
</html>
